htpasswd - Manage user files for basic authentication

htpasswd is used to create and update the flat-files used to
store usernames and password for basic authentication of HTTP users. If
htpasswd cannot access a file, such as not being able to write
to the output file or not being able to read the file in order to update it,
it returns an error status and makes no changes.

Resources available from the Apache HTTP server can be restricted to
just the users listed in the files created by htpasswd. This
program can only manage usernames and passwords stored in a flat-file. It
can encrypt and display password information for use in other types of data
stores, though. To use a DBM database see dbmmanage or
htdbm.

htpasswd encrypts passwords using either bcrypt,
a version of MD5 modified for Apache, SHA1, or the system's
crypt() routine. Files
managed by htpasswd may contain a mixture of different encoding
types of passwords; some
user records may have bcrypt or MD5-encrypted passwords while others in the
same file may have passwords encrypted with crypt().

This manual page only lists the command line arguments. For details of
the directives necessary to configure user authentication in
httpd see the Apache manual, which is part of the
Apache distribution or can be found at http://httpd.apache.org/.

Use batch mode; i.e., get the password from the command line
rather than prompting for it. This option should be used with extreme care,
since the password is clearly visible on the command
line. For script use see the -i option.
Available in 2.4.4 and later.

-i

Read the password from stdin without verification (for script usage).

-c

Create the passwdfile. If passwdfile already
exists, it is rewritten and truncated. This option cannot be combined with
the -n option.

-n

Display the results on standard output rather than updating a file.
This is useful for generating password records acceptable to Apache for
inclusion in non-text data stores. This option changes the syntax of the
command line, since the passwdfile argument (usually the first
one) is omitted. It cannot be combined with the -c option.

-m

Use MD5 encryption for passwords. This is the default (since version
2.2.18).

-B

Use bcrypt encryption for passwords. This is currently considered to
be very secure.

-C

This flag is only allowed in combination with -B (bcrypt
encryption). It sets the computing time used for the bcrypt algorithm
(higher is more secure but slower, default: 5, valid: 4 to 31).

-d

Use crypt() encryption for passwords. This is not
supported by the httpd server on Windows and
Netware. This algorithm limits the password length to 8 characters.
This algorithm is insecure by today's standards.
It used to be the default algorithm until version 2.2.17.

htpasswd returns a zero status ("true") if the username and
password have been successfully added or updated in the
passwdfile. htpasswd returns 1 if it
encounters some problem accessing files, 2 if there was a
syntax problem with the command line, 3 if the password was
entered interactively and the verification entry didn't match,
4 if its operation was interrupted, 5 if a value
is too long (username, filename, password, or final computed record),
6 if the username contains illegal characters (see the
Restrictions section), and 7
if the file is not a valid password file.

Adds or modifies the password for user jsmith. The user
is prompted for the password. The password will be encrypted using the
modified Apache MD5 algorithm. If the file does not exist,
htpasswd will do nothing except return an error.

htpasswd -c /home/doe/public_html/.htpasswd jane

Creates a new file and stores a record in it for user jane.
The user is prompted for the password. If the file exists and cannot be
read, or cannot be written, it is not altered and htpasswd
will display a message and return an error status.

htpasswd -db /usr/web/.htpasswd-all jones Pwd4Steve

Encrypts the password from the command line (Pwd4Steve)
using the crypt() algorithm, and stores it in the specified
file.

Web password files such as those managed by htpasswd should
not be within the Web server's URI space -- that is, they should
not be fetchable with a browser.

This program is not safe as a setuid executable. Do not make it
setuid.

The use of the -b option is discouraged, since when it is
used the unencrypted password appears on the command line.

When using the crypt() algorithm, note that only the first
8 characters of the password are used to form the password. If the supplied
password is longer, the extra characters will be silently discarded.

The SHA encryption format does not use salting: for a given password,
there is only one encrypted representation. The crypt() and
MD5 formats permute the representation by prepending a random salt string,
to make dictionary attacks against the passwords more difficult.

Notice:This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our mailing lists.